December in Cullman is the cloudiest month of the year. In December, the weather in Cullman is typically warm. Average daily high temperature in December is about 10 degrees above zero. On average, Cullman has 9 rainy, 9 sunny, 8 partly cloudy, and 5 cloudy days in December. The rains are usually heavy. December as well as January, February, and July is considered the most uncomfortable time to visit Cullman.